Caustic Bronco

Official rulings

1. “Saddle N” means “Tap any number of other untapped creatures you control with total power N or greater: This permanent becomes saddled until end of turn. Activate only as a sorcery.” (2024-04-12)
2. If a permanent becomes a copy of a saddled Mount, the copy won’t be saddled. (2024-04-12)
3. You may activate a permanent’s saddle ability even if that permanent is already saddled. (2024-04-12)
4. “Saddled” isn’t an ability that a creature has. It’s just something true about that creature. It won’t stop being saddled until the turn ends or it leaves the battlefield. (2024-04-12)
5. Creatures with saddle can attack or block as normal even if they aren’t saddled. (2024-04-12)
6. If the revealed card doesn’t have a mana cost (because it’s a land card, for example), its mana value is 0. (2024-04-12)
7. If the revealed card is a split card, that card’s mana value is based on the combined mana cost of its two halves. (2024-04-12)
8. If Caustic Bronco isn’t on the battlefield as its triggered ability resolves, use whether it was saddled or not before it left the battlefield to determine who loses life. (2024-04-12)
9. An ability that triggers when a creature “attacks while saddled” will trigger only if that creature was saddled when it was declared as an attacker. (2024-04-12)
10. If the revealed card’s mana cost includes {X}, X is 0 for the purpose of determining its mana value. (2024-04-12)